It was supposed to be a straightforward new postage stamp to mark François Hollande's presidency: a more youthful depiction of Marianne, the feminine symbol of the French Republic, reflecting the Socialist president's promise to help the younger generation.

Instead, the portrait has sparked a spat on the political right after one of its designers said it was partially inspired by Inna Shevchenko, a leading member of the feminist activist group Femen.

The designers, David Kawena and Olivier Ciappa, had previously said their inspirations ran from the Renaissance to French comic strips and Japanese manga. But after the stamp's launch on Sunday, Ciappa tweeted: "For all those who are asking who the model was for Marianne, it's a mix of several women, but above all Inna Shevchenko, founder of Femen."

Christine Boutin, a former minister under Nicolas Sarkozy and founder of the Christian Democrat party, tweeted her disgust and her party called for a boycott of "this outrageous stamp", saying it was an attack "on the dignity of women and the sovereignty of France" and should immediately be withdrawn.

Inna Shevchenko, a member of the women's rights group Femen. Photograph: Charles Platiau/Reuters

Femen, which often stages topless street protests, was started in Ukraine but is now based in Paris after Shevchenko was granted political asylum following outrage at her felling of a giant cross in Ukraine in support of the Russian band Pussy Riot.

Femen's most high-profile protests in France have targeted the street demonstrations against same-sex marriage. It also recently staged an anti-fascist protest in Notre Dame cathedral and attempted to ambush the French president at an airshow.

Ciappa, whose exhibition of photographs of imagined gay couples was vandalised in Paris the anti same-sex marriage protests, wrote on Facebook on Monday that he had received "messages of threats and hatred" against him on Twitter, "some violent and some funny, such as Christine Boutin's call to boycott my stamp".

Shevchenko tweeted: "Femen is on French stamp. Now all homophobes, extremists, fascists will have to lick my ass when they want to send a letter."

Several French artists have designed different Mariannes for French stamps, but this is thought to be the first inspired in part by a woman who isn't French.

Four years ago, Inna Shevchenko had never even heard of feminism – today she is leader of the infamous topless protest group, Femen. Despite death threats, arrests and attacks, she defends 'the feminist al-Qaida'